How long does USPS keep tracking info?

USPS Tracking service - up to 120 days Signature Confirmation service - up to one (1) year Priority Mail Express service, Certified Mail service, Registered Mail service, and Numbered International Mail services - up to two (2) years Adult Signature Required / Adult Signature Restricted Delivery Mail - update to three (3) years Archived tracking information can be requested multiple times within the above applicable timeframes.